Although most cellular/mobile devices still support 2G, carriers in numerous countries worldwide have already begun the complete 2G shutdown on their networks to free spectrum for 3G, 4G and 5G services.
Embedded modems such as automotive (OnStar) and alarm systems may again be impacted by these shutdowns.
In developing regions, I anticipate 2G networks will linger for several more years, due to the persistence of flip phones and other legacy devices that have at most 3G capability.

Previously, in 2008 1G AMPS and 2G D-AMPS were shutdown in the USA.
In June 2013, Sprint shutdown the Nextel iDEN network, now used successfully by Sprint as
LTE band 26.
AT&T shutdown their 2G network in December 2016.

Future 2G shutdown

Those designing IoT and other embedded devices with cellular modems should look to LPWA 4G LTE, particularly Cat M1 and NB1 to help ensure global functionality.
Yes, each region has its unique LTE bands, but often OEM modules with the same pinout have region-specific models.
OEM LTE modules will incorporate at least some bands for each region, so that global LTE roaming for even inexpensive LTE modems will become increasingly common.